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Ask HN: In JavaScript, changing the value of an array item not advised?

by mcdoh on 7/1/10, 6:30 PM with 2 comments

I'm reading through jQuery Fundamentals (http://www.rebeccamurphey.com/jqfundamentals/#javascript-basics.examples.change-array-value) and this tip in the JavaScript chapter surprised me: While it's possible to change the value of an array item as shown in Example 2.28, “Changing the value of an array item”, it's generally not advised.

I wouldn't think just changing the value of an array element could cause a problem. Is this truly inadvisable or was this written in error?

by byoung2 on 7/1/10, 6:58 PM
It shouldn't be a problem with strings and numerics in arrays (the array contains copies of the values), but with arrays of functions/objects, the elements of the array are not copies, but the actual objects themselves. So if you change an object in the array, the object itself changes (and vice versa).